According to the records in Pliny Sr's Natural History, in 600 BC, Phoenicians made primitive soap from sheep fat and wood ash for skin care and treatment, and it was not until the 2nd century AD that it was discovered that it had an important washing function. 179 1 year n. Nicola Leblanc used brine to make soda ash and lime to causticize soda ash to produce caustic soda. Since then, soap has changed from manual production to industrial production. At the end of 19, soap production entered an important development stage by adopting direct steam cooking method.
During the First World War, due to the tight supply of animal and vegetable oils, Germany first developed a synthetic detergent, whose main component was short-chain alkyl naphthalene sulfonate, which was formed by combining propanol or butanol with naphthalene and then sulfonating it, collectively called Nekal.
In the late 1920s, long-chain fatty alcohols were sulfated and neutralized into fatty alcohol sodium sulfate. At that time, only some sodium sulfate was added and sold as a synthetic detergent. In the early 1960s, with the development of petrochemical industry, the United States produced long-chain alkyl aryl sulfonates, in which the aryl group was made of benzene and the alkyl group was made of kerosene fraction. This alkyl aryl sulfonate is sold directly as a detergent, or some sodium sulfate is added. After World War II, tetrapropene was polymerized from propylene. Instead of kerosene fraction, it combines with benzene to become alkylbenzene, and then sulfonates and neutralizes to become sodium alkylbenzene sulfonate. Because of its low price and good performance, it developed rapidly and occupied a dominant position until the early 1960s. At that time, most synthetic detergents in the world were made of this surfactant. 1960 s, due to the branched chain in the chemical structure of tetrapropene, it is not easy to be biodegraded, causing environmental pollution. Therefore, linear alkylbenzene gradually replaced tetrapropylenealkylbenzene.
With the development of chemical industry, excellent surfactants such as sodium alkylbenzene sulfonate are used as the basic components, and other surfactants and various additives are also used to improve the washing effect. During World War II, Germany began to use carboxymethyl cellulose as an auxiliary agent for synthetic detergent to eliminate the problem of redeposition of dirt. By the end of World War II, alkaline substances such as carbonate, silicate and phosphate were used as additives for synthetic detergents. The use of polyphosphate is an important step in the development of synthetic detergent industry. Tetrasodium pyrophosphate was first used, and then sodium tripolyphosphate was used, which achieved good washing effect. However, by the end of 1960' s, a large amount of sodium tripolyphosphate was used in synthetic detergents, which was discharged into sewers after use, polluting river water sources and causing the problem of "overnutrition". Some countries have banned or restricted its use and replaced it with zeolite and other substitutes.
Since 1950s, the continuous production process of soap has been realized, and the product quality has been greatly improved, but there is no breakthrough in performance and application. Although the output increased slightly, its proportion in washing products showed a downward trend. The proportion of soap in 1960 is about 63%, which has dropped to 29% in 1982, and began to rise in the 1980s. 1987 The world output has exceeded 8 million tons.
China established Pancreas Company in Tianjin 1903. 1907, Mao Yu soap factory was established in Shanghai, which is the first two soap factories in China. Since then, some soap factories have been established in Nanjing, Hangzhou, Chongqing, Shenyang, Dalian, Wuhan and other cities, and handmade soap workshops have also been established in some areas. Until 1949, there was only soap industry in China, and most of them were manual workshops with small scale and poor equipment. Only in several big cities, such as Shanghai and Tianjin, can there be several slightly larger machine factories. 1949 The output of soap was only 30,000 tons. 1959 soap output reached 410.5 million tons. In the same year, the production of synthetic detergent began, with an output of 5700 tons. Since 1960, with the development of synthetic detergents, the production of raw materials such as alkyl benzene and sodium tripolyphosphate has gradually developed. 196 1 year, paraffin wax was developed to produce synthetic fatty acids for soap. After 1978, the production of washing products developed rapidly, and the variety of colors gradually increased. For example, many varieties of washing powder have been developed, such as compounding, adding enzymes, sterilizing, adding color, flavor and concentration, etc. Among liquid detergents, various special detergents have been developed, such as washing tableware, fruits and vegetables, bathtubs, stoves, screens, glass, enamel products, carpets and shampoos. Skin care, soap and shower gel with certain curative effects have also been developed, and products suitable for the elderly, women and children have been developed. The application fields of industrial detergents are constantly expanding, and various surfactants and industrial detergents produced have been used in machinery, metallurgy, petroleum, chemical fiber, textile, printing and dyeing, leather, paper making and other fields. 1985 The total output of washing products reached 2 million tons, including 996,000 tons of soap and 0.004 million tons of synthetic detergent. Up to now, China's washing products industry has formed a washing products industrial system with a certain scale, mainly soap and synthetic detergent, including main raw materials and accessories.
Decontamination mechanism: Dirt on clothes is often a mixture of liquid and solid, which is adsorbed on the surface of clothing fibers or enters between fiber tissues through physical and chemical action or even mechanical action, which will not only destroy the appearance of clothes, but also damage the tissues of clothes and shorten their service life. The decontamination process of washing products can be simply expressed as:
Fabric dirt+detergent → fabric dirt+detergent
(dirty clothes) (dirty washing liquid)
The mechanism of decontamination process is complicated, which generally includes the following physical and chemical actions:
(1) Wetting: Because the surfactant in the washing liquid can reduce the surface tension of water and increase the wetting ability of water to the fabric, the washing liquid can fully penetrate between the fibers, and the surfactant molecules can generate affinity with the dirt on the washed fabric, so that the dirt can be separated from the fabric.
② Adsorption: There are interfaces between water and washed fabric, and between water and dirt. After the effective components in the washing liquid are adsorbed by the fabric and dirt, the interface energy and the electrostatic attraction of the fabric to the dirt are changed, so that the dirt is suspended or emulsified in water.
③ Solubilization: dirt is sandwiched between the micelle layers of the washing liquid, resulting in solubilization.
(4) Mechanical action: When the dirt and the fabric adsorb the surfactant, under the action of manual scrubbing or mechanical stirring, the dirt and the fabric are separated and dispersed in the solution, and the dirt can be removed by repeated rinsing.
Trend: The annual output of washing products in the world has exceeded 30 million tons in1980s. After the rapid development of synthetic detergent industry in1960 ~1970s, the development speed began to slow down in1980s, but the development speed of countries in the world is different. The consumption of washing products in developed countries has reached a high level and the development tends to be stable. Countries such as Asia and Africa will develop rapidly with the improvement of living standards. Among washing products, synthetic detergent develops faster than soap. However, the development of synthetic detergents is also restricted by environmental protection, ecological balance, fabric structure change and energy saving. Synthetic detergents tend to be safe and biodegradable in the selection and proportion of surfactants and additives. In terms of product structure, it is developing in the direction of convenient use and multi-function. Because of high energy consumption, large investment and high production cost, tower spray molding of washing powder will gradually turn to tower-less molding, especially agglomeration molding.